Every year before summer starts people ask me if it is going to be a hot summer. I usually tell them that it is Columbia, South Carolina, of course it is going to be hot. However, this summer has been a little different and not what I expected. Let me give you a couple of examples.
Columbia, South Carolina had its 13th coldest May on record (Avg. T=68.9˚F) this year. That was followed by the 17th coldest June on record (Avg. T=76.2˚F). So maybe it will not be so hot this summer. Then came July. The first 8 days have put the month on track for the 8th warmest July even though the highest temperature has been 95˚F. It has been the low temperature pushing the average up as it has put the month on track for the 3rd warmest low temperature.
When you see the reports for Texas and the Southwest about the current heat wave this does not seem so bad. I was amazed how far north the heat has been driven. Take the example of the weather station at Norman Wells in the Northwest Territories in Canada. It is at about latitude 65˚N and yesterday it reported a high temperature of 100˚F. This beat its previous all-time high temperature record by 5˚F. On top of that it had visibilities of about a mile in smoke from wildfires. Truly epic. A cold front passed late in the day and winds shifted blowing up to 40 mph. This blew the smoke away and lowered the temperature.
I have been following the media reports of the heat wave this year. As meteorologists we often do not know how the pattern will evolve until we get into the season. The models have not always given us a clear picture, but now we have a better sense of what lies ahead.
High pressure in the middle of the atmosphere was centered over Texas early in the summer which was responsible for the start of the heat wave there. Over time it expanded and now stretches from Florida to Texas to the Southwest. The high pressure is centered over New Mexico and by the end of the week it will be over Arizona. This will push the heat wave into California and north to Washington state.
The atmospheric pattern at 500 mb (~18,000 ft.). This is the forecast for next Sunday July 16, 2023 from the European model. The H represents the center of the high pressure system and the L the low pressure system. These will not move much over the next week.
Temperatures will be hotter than normal across much of the southern U.S. by next weekend. Readings in Death Valley, California may approach 130˚F. Even in the central valley of California temperatures will be above 110˚F. (The lowest relative humidity I ever experienced was in Fresno, CA at 4%. It was drier than Death Valley.) Parts of South Carolina may approach 100˚F with heat indices in the range of 105-108˚F. No doubt the heat will continue to be news.
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| Projected high temperatures for Sunday July 16, 2023 from the European model. Actual temperatures may differ slightly, but the overall pattern has higher confidence. It will be hot from the intermountain region, the Southwest, Texas into the Southeast. |
Notice the low-pressure system in Canada. The combined flow around it and the high over Arizona will push cooler air into the Midwest. The 6 to 10 day forecast reflects the evolving pattern.
From the National Weather Service. This is the 6 to 10 day outlook for July 15-19 made on July 9. The cool weather in the central U.S. will be short-lived. The heat wave will begin to expand northward after this time.
However, this will be temporary. The computer models suggest that the heat will begin to build north and east during the third week of July. The area that may escape much of the heat will likely be around the Great Lakes to the Northeast.
Don’t think that this is the end of the story. I have only looked at the temperature here. There will be areas struck by severe thunderstorms and floods mainly in areas outside the heat wave. We have already seen examples of this over the past few weeks. Thus, the summer of extremes is likely to continue.
I wonder what August will look like.
